Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:
The intensity of illumination on a surface from a expenditure also increases by 12%. How much source of light varies inversely as the square of the percent does his savings increase? (M.A.T., 2010) distance of the surface from the source. The effect
(a)6%
(b)7% of moving a piece of paper 3 times as far from the
(c)11%
(d)13% source is to
Answer
Answer (as printed): D
Explanation
I α 2 ⇒ I = 2 (where k is a constant) ⇒ k = I d2. d d k I d2 I \ Inew = = = . (3d)2 9d 2 9
Explanation as extracted from the printed page; notation may be imperfect.